CN101555417B - Denitrifier and preparation method thereof - Google Patents

Abstract

The invention relates to a denitrification agent, the denitrification agent is composed of 60-90wt% _SiO2 and 10-40wt% _Al2O3 , _preferably the content of _SiO2 is 80wt%, and the content of _Al2O3 is 20wt% _. The denitrification agent of the present invention has a specific surface area of 500-1000m ² /g, a pore volume of 0.6-1.2ml/g, and a percentage of its pore diameter of 3-10nm is greater than 80%. The present invention further discloses the preparation method of the above-mentioned denitrification agent. The denitrification agent of the present invention prepared by the preparation method has a relatively suitable acid center and has strong selectivity to basic nitrogen compounds; in addition, the The denitrification agent can remove as high as 99.9% of trace nitrogen compounds and relatively large amounts of nitrogen compounds. The most important thing is that the denitrification agent can achieve the above-mentioned high denitrification rate at the same time, and its nitrogen adsorption capacity can be as high as 2.2 %.

Description

A kind of denitrification agent and preparation method thereof

technical field

The invention relates to an adsorption denitrification agent and a preparation method thereof, in particular to an adsorption denitrification agent for catalytic diesel oil, and belongs to the technical field of purification.

Background technique

Diesel fuel is the most important power fuel in developing countries. It has high thermal power efficiency, low fuel specific consumption, and is relatively economical. high share. In the actual use process, the requirements for diesel performance are mainly divided into the following aspects: (1) ignitability, to ensure that diesel has a high and suitable cetane number through treatment; (2) evaporability, that is, to ensure that diesel oil It has a suitable light distillate, which ensures that the diesel has good startability (easy to burn) and at the same time does not cause knocking; (3) higher freezing point, the freezing point of diesel oil is closely related to its fraction, The heavier the fraction, the higher its freezing point. However, the above-mentioned performance requirements cannot be met by the diesel oil currently produced in my country, so certain treatments are required.

Diesel produced in my country contains a lot of organic sulfides and nitrogen compounds. The nitrogen compounds are divided into two categories: basic nitrogen compounds and non-basic nitrogen compounds; common basic nitrogen compounds mainly include aliphatic amines, pyridine Common non-basic nitrogen compounds mainly include pyrroles, indoles, carbazoles, phenazines, nitriles and amides. The basic nitrogen compounds in diesel oil are mainly quinolines and anilines, and the non-basic nitrogen compounds are mainly indoles and carbazoles, and it has been tested that the non-basic nitrogen compounds in diesel oil are the basic nitrogen compounds. 3 to 5 times of that.

Among the above-mentioned nitrogen oxides, non-basic nitrogen compounds have little effect on subsequent diesel oil hydrotreating; while for basic nitrogen compounds, especially basic nitrogen compounds such as lutidine and alkylamines On the one hand, it will cause the color and stability of the oil to deteriorate, and on the other hand, it will also affect the activity of the catalyst in the subsequent catalytic hydrotreating process, and even lead to its poisoning and deactivation, which directly affects the subsequent desulfurization of diesel hydrotreating The precision of desulfurization is reduced, and the nitride itself will consume part of the hydrogen, thereby increasing the overall hydrogen consumption in the hydrofining process and wasting energy.

Therefore, removing basic nitrogen compounds in diesel as much as possible is an effective means to improve the efficiency of diesel hydrotreating. At present, there are two methods commonly used to remove basic nitrogen compounds in diesel oil, one is to remove basic nitrogen compounds through hydrocatalytic treatment, and the other is to use adsorption denitrification agent to directly remove basic nitrogen compounds in diesel oil. Nitride is adsorbed.

Adsorption denitrification is the use of solid adsorbents for the strong adsorption of polar compounds to remove nitrogen compounds in oil. Commonly used adsorption denitrification agents are generally polar substances, and require large specific surface area, large porosity, strong acidity and large pore size. It is best to have acid centers with different intensity distributions to increase the ability of selective denitrification; Examples of the above-mentioned substances include silica gel, activated alumina, activated carbon, molecular sieves, diatomaceous earth, and clay.

Clay is used as a denitrification agent, which usually forms an ancient acid-clay or solvent-clay system with acid or solvent, so as to remove nitrogen compounds in oil. Although clay can be used as a denitrification agent, if you want to use clay to obtain a higher refining depth, then the amount of clay required is huge, which will reduce the yield of refined oil due to the addition of a large amount of clay; and nitrogen adsorption The waste white clay after chlorination cannot be recycled, and the pollution to the environment is extremely serious. For the diatomaceous earth denitrification agent, it also has the above-mentioned problems. Therefore, as humans pay more and more attention to environmental protection, the refining technology of using clay and diatomaceous earth as denitrification agents for adsorption denitrification tends to be gradually replaced in recent years.

U.S. patent document US6248230B1 discloses a method for preparing clean hydrocarbon fuels. In this method, hydrocarbon raw materials need to be refined, and the adsorbent used to remove nitrogen compounds in hydrocarbon fuels uses activated alumina, molecular sieves, and carbon dioxide. silicone gel. Tests have shown that using silica gel with a specific surface area of 733.2m ² /g and a pore diameter of 20.19 angstroms as a denitrification agent, the denitrification rate can only reach 7%.

With the development of technology, Chinese patent document CN101003743A discloses a kind of adsorption refining preparation used in the solvent refining of lubricating oil base oil. The main component of the refining preparation is a porous substance with alumina and silicon oxide as the main components. The above-mentioned main components of the refined preparation are mainly obtained from montmorillonite in natural boronite ore through solvent modification, drying and screening. This patent uses montmorillonite as a raw material and modifies it, which greatly improves the denitrification rate of the denitrification agent. However, since the raw material contains some impurity components, its adsorption accuracy for the above-mentioned adsorption refining agent will be limited. A certain degree of influence leads to a decrease in the adsorption rate, which is obviously manifested in that the denitrification rate of the adsorption refining preparation disclosed in this patent can only reach 79%.

US Patent No. 4,137,154 discloses a process for removing nitrides from an organic medium. The denitrification agent used may be amorphous silica-alumina or a mixture of silica and alumina. Tests have shown that the amorphous silica-alumina described in this patent document is composed of 5 to 95 wt% of silica and the balance of alumina, and this substance only has a trace amount of nitride (such as 0.2ppm) as high as 99.9%. The removal rate, and for the nitride content of 7.4ppm, the removal rate of amorphous silicon oxide-alumina can only reach 76.9%; in addition, in this patent document, for the amorphous silicon oxide- The evaluation of the denitrification performance of alumina only uses the nitrogen removal rate to measure, but does not disclose any data about the nitrogen adsorption capacity of the denitrification agent. In fact, for any denitrification agent, the high denitrification Efficiency and high adsorption nitrogen capacity have the same important value, only have high denitrification rate but no high adsorption nitrogen capacity, then in the process of denitrification treatment, it is necessary to constantly replace the denitrification agent to satisfy its adsorption of nitrogen compounds, so that The efficiency of denitrification treatment is greatly reduced. It is also due to the limitation of the nitrogen adsorption capacity of the denitrification agent itself that the removal rate of trace nitrogen compounds can reach 99.9%, while the removal rate of nitrogen compounds with a content of only 7.4ppm can only reach 76.9%. %.

For the preparation method of the above-mentioned denitrification agent, the British patent document GB2267486A discloses a preparation method of amorphous silica-alumina, which is to add a silicon-containing substance (such as tetraethyl orthosilicate) to an ethanol solution, and then add The aqueous solution containing aluminum ions is controlled at a pH of 0.7 to 2.4 to form a silica-alumina sol, and then the above-mentioned silica-alumina sol is roasted at 200-600°C to prepare amorphous silica-oxide with a microporous structure. aluminum. In this preparation method, there are the following technical problems: (1) first prepare an aqueous solution containing aluminum ions, then when it is added to a silicon-containing ethanol solution, a part of the aluminum ions will be hydrolyzed to form a sol, and the other part will generate aluminum ions. ion precipitation, thereby reducing the productive rate of silica-alumina sol; (2) after the aqueous solution containing aluminum ions is hydrolyzed into gel or precipitated, it is added to the silicon-containing ethanol solution, which will affect the sufficient hydrolysis of silicon-containing substances into (3) The pore size distribution of the silica-alumina denitrification agent prepared by the above preparation method is not concentrated, and the maximum micropore distribution can only reach 73%.

Contents of the invention

The first technical problem to be solved by the present invention is that the silicon-aluminum denitrification agent in the prior art is only suitable for the removal of trace nitrides, and for the removal of trace nitrides, it only has a relatively high nitride removal rate. There is no problem of high adsorption nitrogen capacity, and thus provides a method not only suitable for the removal of trace nitrogen compounds, but also suitable for the removal of larger amounts of nitrogen compounds, and has high nitrogen removal rate and high adsorption at the same time Nitrogen capacity silicon aluminum denitrification agent.

The second technical problem to be solved by the present invention is that in the method for preparing silicon-aluminum denitrification agent in the prior art, it is easy to affect the sol generation rate due to the inability to accurately control hydrolysis and gelation, and the pore size of the prepared silicon-alumina denitrification agent The distribution is not concentrated enough, and a method for preparing a silicon-alumina denitrification agent that can accurately control the formation of the silica-alumina hydrolysis sol and ensure that it is fully hydrolyzed into a gel and has a relatively high micropore size distribution ratio.

In order to solve the above technical problems, the present invention provides an adsorption denitrification agent, which is composed of 60-90wt% SiO ₂ and 10-40wt% Al ₂ O ₃ . Preferably, the content of SiO ₂ in the denitrification agent is 80 wt%, and the content of Al ₂ O ₃ is 20 wt%.

Wherein, the specific surface area of the denitrification agent is 500-1000m ² /g, and the pore volume is 0.6-1.2ml/g. The percentage of the denitrification agent with a pore diameter of 3-10 nm is greater than 80%.

On the basis of disclosing the above-mentioned denitrification agent, the present invention further discloses a preparation method of the denitrification agent for solving the above-mentioned second technical problem, which includes the following steps:

(a) Add an appropriate amount of water to the aluminum-containing raw material, the molar ratio of the water to the alumina in the product is 110-280, perform hydrolysis at 83-87°C, then add nitric acid solution for degumming, and then dissolve the gel at 90-95°C The hydrolysis is carried out at least 1 h at ℃, and the sol product I is generated after cooling;

(b) adding an appropriate amount of absolute ethanol to the silicon-containing raw material, the mass ratio of the absolute ethanol to the silicon-containing raw material is 0.5-0.7, stirring the above-mentioned materials evenly, and then adding ethanol and water with a volume ratio of 1:1, The molar ratio of the total amount of water in the solution to the silicon dioxide in the product is 6-10, and then adding nitric acid solution to adjust the pH value of the above solution to 3, and stirring to obtain the sol product II;

(c) Mix and stir the product I and the product II, and add an appropriate amount of surfactant, the molar ratio of the surfactant to the _SiO in the product is 0.15 to 0.35, stir for 3 to 10 hours to directly generate the gel product III, and the above product III Aging at 50-70°C;

(d) Dry the above-mentioned aged product III at 30-50° C. under reduced pressure for at least 0.5 days, and bake it at 500-600° C. for 3-5 hours after molding.

Wherein, the aluminum-containing raw material is one or both of aluminum nitrate and aluminum isopropoxide; the silicon-containing raw material is one or both of methyl orthosilicate and ethyl orthosilicate. The surfactant is an organic amine surfactant with a molecular weight not higher than 600, selected from dodecyl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride, hexadecane One or more of trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, bis-octyl dimethyl ammonium chloride.

In the step (a), the aluminum-containing raw material is hydrolyzed at 85°C for 1 hour; then the aluminum-containing raw material is hydrolyzed at 90-95°C for 1-2.5 hours. The aging time in the step (c) is 2-3 days. In the step (d), the shaped product III is calcined at 550°C.

The preparation method of the denitrification agent according to the present invention needs to prepare aluminum sol and silica sol respectively; for the preparation of aluminum sol, it needs to be realized through two hydrolysis steps, firstly, add an appropriate amount of water to the aluminum-containing raw material, and at 83-87 The hydrolysis is carried out at ℃, the hydrolysis time is preferably 1h, and nitric acid solution can be added to it for degumming. The reason for degumming is that the aqueous solution of aluminum-containing raw materials is easily hydrolyzed during the gelation process, and the formation of precipitates greatly affects The formation of aluminum sol will affect the pore size and pore size distribution of the prepared silicon-alumina denitrification agent. Adding nitric acid can eliminate the aluminum precipitate generated in the above hydrolysis process, so that the secondary setting temperature is 90 ~ 95 ° C When performing hydrolysis, ensure that the aluminum-containing raw materials after degelation are hydrolyzed into gels smoothly; among them, the time for hydrolysis at 90-95°C is limited to at least 1 hour, in order to ensure that the hydrolysis into gels is fully completed, and the time for the hydrolysis to complete 1 to 2.5 hours can be preferred. For the preparation of silicon-containing sol, it is first necessary to disperse the silicon-containing raw material in an appropriate amount of absolute ethanol, and then add ethanol and water with a volume ratio of 1:1 to the above-mentioned ethanol solution dispersed with silicon-containing raw materials. Adding absolute ethanol before adding ethanol and water mixture is because the silicon-containing raw material is hydrolyzed violently when it encounters water, and dispersing it in absolute ethanol can control its hydrolysis rate; adding nitric acid solution to adjust the pH value of the above solution to 3, the pH On the one hand, it ensures that the silicon-containing raw materials are fully hydrolyzed to form silica sol without precipitation, and also ensures the concentrated distribution of the pore size of the subsequent denitrification agent. On the other hand, it also provides the appropriate acid center necessary for the denitrification agent, which is more conducive Adsorption and regeneration of basic nitrogen compounds by denitrification agent.

As mentioned above, the selection of aluminum-containing raw materials and silicon-containing raw materials is beneficial to control the pH value of the sol, thereby ensuring a suitable acid center for the final denitrification agent prepared.

After the above-mentioned aluminum sol and silica sol are prepared, mix the above two substances and then add an appropriate amount of surfactant as a surface-directing agent. When the system is added with an appropriate amount of surfactant, Spinodal (spinodal) can be induced during the reaction process. Phase separation, the final composite oxides have a three-dimensional spatially continuous structure dominated by mesoporous structures with macropores, which can provide efficient material transport channels. From the perspective of the type of surfactant, it can be any of the commercially available ones that can satisfy the above-mentioned induced Spinodal phase separation and can be prepared to have a three-dimensional spatially continuous surface of a composite oxide mainly composed of mesopores and a macroporous structure. Active agent; Wherein, preferred molecular weight is not higher than the organic amine surfactant of 600, is because this kind of surfactant can not only reach above-mentioned induced Spinodal phase separation and can prepare to have three-dimensional spatial continuity mainly with mesoporous amalgamation The purpose of the composite oxide with a macroporous structure, and its cost is low, the most important thing is that it can well adjust the subsequent pH value through stirring to ensure that a suitable acidic center is provided for the final product. In terms of the amount of surfactant added, the added amount should not be too large, otherwise it will easily lead to too much macroporous structure and too little mesopore structure of the denitrifying agent, which will reduce the adsorption capacity of the denitrifying agent; similarly, the added amount should not be too large. Otherwise, it will easily lead to too little macroporous structure of the denitrification agent, and the interior of the denitrification agent cannot provide efficient material transmission channels, reducing the adsorption capacity of the denitrification agent; the addition of the above surfactants can not only play the role of surface directing agent It can also play a role in adjusting the pH value. By stirring the product I and product II after adding the surfactant, and limiting the stirring time to 3-10 hours, the pH value of the sol will increase with the stirring, and finally generate Gel product III with a suitable acid center; after that, set 50-70°C for aging, which is beneficial to generate a gel product with a suitable pore size; the best aging time is 2-3 days to achieve the purpose of gel aging.

Finally, it is necessary to dry the above-mentioned aged product III at 30-50°C under reduced pressure for at least 0.5 days. The water and ethanol in the above-mentioned preparation process can be removed. Carry out calcination for 3-5 hours, preferably at a calcination temperature of 550°C, which is more conducive to the formation of the pore structure of the denitrification agent.

Al ₂ O ₃ -SiO ₂ composite oxide porous materials with both mesoporous and macroporous structures (mainly mesopores) were synthesized by the new sol-gel method with the addition of organic surfactants. The synthesized materials have huge Large specific surface area and developed pore structure, and has solid acidity. And these adsorbent materials with well-developed pore structure are used to adsorb and remove basic nitrogen compounds in diesel oil, and provide a new method for further producing ultra-low nitrogen clean diesel oil.

The present invention has the following advantages:

(1) The denitrification agent prepared by the preparation method of the silicon aluminum denitrification agent according to the present invention can have a removal rate of up to 99.9% for trace nitrides; in addition, the denitrification agent can also be applied to a higher content The removal of nitrides, such as the nitrides with a content of 500ppm, the denitrification agent of the present invention can realize that its removal rate can reach 99.9%; the most important thing is that the denitrification agent achieves the above-mentioned high denitrification At the same time, its adsorption nitrogen capacity can still be as high as 2.2%;

(2) The denitrification agent of the present invention prepared by the preparation method of the silicon-aluminum denitrification agent of the present invention has a high specific surface area and abundant acid centers on its surface, and the acid strength of these acid centers It is not high, which is conducive to the selective adsorption of basic nitrogen compounds; in addition, the denitrification agent with a suitable acidic center is easy to regenerate and can be reused;

(3) The preparation method of the silicon-aluminum denitrification agent of the present invention adopts the method of separately preparing aluminum sol and silica sol and then mixing and preparing the denitrification agent, and the aluminum sol is well controlled by secondary hydrolysis combined with nitric acid degelation The formation of aluminum precipitates avoids the problem of reducing the yield of sol; in addition, the hydrolysis and gelation process of silicon-containing substances is controlled by adding absolute ethanol in advance; thus ensuring that the prepared material has a uniform and regular pore structure as a whole , appropriate pore size and concentrated pore size distribution provide the necessary conditions.

Detailed ways

The present invention will further describe the denitrification agent of the present invention and its preparation method in conjunction with the following examples:

Example 1

Weigh 17.8g of aluminum isopropoxide and add it to 200g of water, heat to 83°C for 0.5 hour for hydrolysis, then use 1.7g of nitric acid for degumming, hydrolyze for 3 hours at 90°C, and produce product W1 after cooling.

Weigh 138.7g of tetraethyl orthosilicate, add 69.4g of absolute ethanol, stir for 10 minutes, then add 214.5g of ethanol and water mixed solution with a volume ratio of 1:1, adjust the pH value of the above solution to 3 with nitric acid, Stirring for 1 hour yielded product W2.

The product W1 and the product W2 were mixed and stirred, 34 g of surfactant p-dodecyldimethylbenzyl ammonium chloride was added, and stirred for 3 hours to obtain a gel product W3, which was aged at 50° C. for 5 days. The above-mentioned aged product was dried under reduced pressure at 30°C for 3 days, and baked at 500°C for 5 hours after molding to obtain a denitrification agent product with an alumina content of 10wt% and a silica content of 90wt%.

Tests show that the specific surface area of the denitrification agent product is 580m ² /g, the pore volume is 0.6ml/g, and the percentage of the pore diameter is 3-10nm is 85%.

Example 2

Weigh 40g of aluminum isopropoxide and add it to 400g of water, heat to 85°C for 1.0 hour for hydrolysis, then use 3.8g of nitric acid for degumming, hydrolyze for 2.5 hours at 91°C, and produce product W1 after cooling.

Weigh 138.7g of tetraethyl orthosilicate, add 97.1g of absolute ethanol, stir for 10 minutes, then add 128.7g of ethanol and water mixed solution with a volume ratio of 1:1, adjust the pH of the above solution to 3 with nitric acid, Stirring for 1 hour yielded product W2.

The product W1 and the product W2 were mixed and stirred, 61 g of surfactant cetyltrimethylammonium bromide was added, and stirred for 5 hours to obtain a gel product W3, which was aged at 55° C. for 3 days. The above-mentioned aged product was dried under reduced pressure at 40° C. for 2 days, and baked at 550° C. for 4 hours after molding to obtain a denitrification agent product with an alumina content of 20 wt % and a silica content of 80 wt %.

Tests show that the specific surface area of the denitrification agent product is 1000m ² /g, the pore volume is 1.2ml/g, and the percentage of the pore diameter is 3-10nm is 90.5%.

Example 3

Weigh 68.7g of aluminum isopropoxide and add it to 847g of water, heat to 86°C for 1.5 hours for hydrolysis, then use 5.7g of nitric acid for degumming, hydrolyze for 2.0 hours at 93°C, and produce product W1 after cooling.

Weigh 138.7g of tetraethyl orthosilicate, add 83g of absolute ethanol, stir for 10 minutes, then add 150g of a mixed solution of ethanol and water with a volume ratio of 1:1, adjust the pH value of the above solution to 3 with nitric acid, and stir for 1 hours, the product W2 is formed.

The product W1 and the product W2 were mixed and stirred, 71 g of surfactant octadecyldimethylbenzyl ammonium chloride was added, and stirred for 7 hours to obtain a gel product W3, which was aged at 60° C. for 2.5 days. The above-mentioned aged product was dried under reduced pressure at 45° C. for 1 day, and baked at 580° C. for 3.5 hours after molding to obtain a denitrification agent with an alumina content of 30 wt % and a silica content of 70 wt %.

Tests show that the specific surface area of the denitrification agent product is 650m ² /g, the pore volume is 0.8ml/g, and the percentage of the pore diameter is 3-10nm is 87%.

Example 4

Weigh 196g of aluminum nitrate and add it to 432g of water, heat to 87°C for 2.0 hours for hydrolysis, then degullify with 9.5g of nitric acid, hydrolyze for 1.0 hour at 95°C, and generate product W1 after cooling.

Weigh 138.7g of tetraethyl orthosilicate, add 80g of absolute ethanol, stir for 10 minutes, then add 172g of ethanol and water mixed solution with a volume ratio of 1:1, adjust the pH value of the above solution to 3 with nitric acid, and stir for 1 hours, the product W2 is formed.

The product W1 and the product W2 were mixed and stirred, 70 g of surfactant bis-octyl dimethyl ammonium chloride was added, and stirred for 8 hours to obtain a gel product W3, which was aged at 65° C. for 2.0 days. The above-mentioned aged product was dried under reduced pressure at 50°C for 0.5 days, and baked at 600°C for 3.0 hours after molding to obtain a denitrification agent with an alumina content of 40 wt% and a silica content of 60 wt%.

Tests show that the specific surface area of the denitrification agent product is 850m ² /g, the pore volume is 0.9ml/g, and the percentage of the pore diameter is 3-10nm is 90%.

Example 5

Weigh 196g of aluminum nitrate and add it to 500g of water, heat to 85°C for 1.0 hour for hydrolysis, then use 9.5g of nitric acid for degumming, hydrolyze for 2.0 hours at 93°C, cool to produce product W1.

Weigh 138.7g of tetraethyl orthosilicate, add 90g of absolute ethanol, stir for 10 minutes, then add a mixed solution of ethanol and water with a volume ratio of 1:1, so that the total amount of absolute ethanol reaches 193g, and adjust to the pH value with nitric acid 3, stirred for 1 hour to generate product W2.

The product W1 and the product W2 were mixed and stirred, 49.3 g of surfactant tetradecyldimethylbenzyl ammonium chloride was added, and stirred for 3 hours to obtain a gel product W3, which was aged at 60° C. for 2 days. The above-mentioned aged product was dried under reduced pressure at 50°C for 1 day, and baked at 550°C for 4 hours after molding to prepare a denitrification agent with an alumina content of 40% and a silica content of 60%.

Tests show that the specific surface area of the denitrification agent product is 900m ² /g, the pore volume is 1.0ml/g, and the percentage of the pore diameter is 3-10nm is 93%.

Example 6

Weigh 196g of aluminum nitrate and add it to 600g of water, heat to 85°C for 1.0 hour for hydrolysis, then use 9.5g of nitric acid for degumming, hydrolyze for 2.0 hours at 93°C, cool to produce product W1.

Weigh 101.3g of methyl orthosilicate, add 60g of absolute ethanol, stir for 10 minutes, then add 180g of ethanol and water mixed solution with a volume ratio of 1:1, adjust the pH value to 3 with nitric acid, stir for 1 hour, and generate Product W2.

The product W1 and the product W2 were mixed and stirred, 75 g of surfactant cetyltrimethylammonium chloride was added, and stirred for 3 hours to obtain a gel product W3, which was aged at 60° C. for 2 days. The above-mentioned aged product was dried under reduced pressure at 50°C for 1 day, and baked at 550°C for 4 hours after molding to prepare a denitrification agent with an alumina content of 40% and a silica content of 60%.

Tests show that the specific surface area of the denitrification agent product is 950m ² /g, the pore volume is 1.1ml/g, and the percentage of the pore diameter is 3-10nm is 91%.

In the preceding examples, what is given is the example of using a single surfactant to prepare the denitrification agent of the present invention. As a changeable embodiment, it is also possible to select any Choose lauryl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, ten Two or more of tetraalkyl dimethyl benzyl ammonium chloride and bis-octyl dimethyl ammonium chloride are added as surfactants. Of course, in addition to the above-mentioned surfactants, any organic amine surfactant with a molecular weight not higher than 600 can be used in the preparation method of the denitrification agent described in the present invention. In addition, any commercially available surfactant that can not only induce Spinodal phase separation but also prepare a composite oxide with a three-dimensional spatially continuous macroporous structure is suitable for the preparation method of the denitrification agent described in the present invention.

Example of Nitrogen Removal Effect Evaluation

For the evaluation test (referring to table 1 result) of the denitrification effect of the denitrification agent prepared in the above-mentioned embodiment, select to carry out in the normal pressure evaluation device, the reactor diameter of the normal pressure evaluation device is 13mm, select the denitrification agent particle size to be 40-60 mesh, the loading amount is 10 grams.

Test conditions: space velocity 1.0h ^-1 , temperature 20-25°C.

Control the hydrogenated diesel containing a certain amount of basic nitrogen to pass through the reactor of the evaluation device, and measure the basic nitrogen content in the diesel at the outlet according to the Chinese petrochemical industry standard SH/T0162-92 "Determination of basic nitrogen in petroleum products" conduct. Dissolve the oil sample in a mixed solvent of benzene-glacial acetic acid, use methyl violet as an indicator, and titrate the basic nitrogen in the sample with perchloric acid-glacial acetic acid standard titration solution until the solution changes from purple to blue. Calculate the content of basic nitrogen compounds in the oil sample according to the concentration and volume of the consumed perchloric acid-glacial acetic acid standard solution. The calculation formula is:

${\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.014</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}$

Wherein, V ₂ is the volume of perchloric acid-glacial acetic acid standard solution consumed by the titration sample, mL; V ₃ is the volume of perchloric acid-glacial acetic acid standard solution consumed by the blank test, mL; c represents perchloric acid-glacial acetic acid standard solution The actual concentration of acetic acid standard solution, mol/L; m is the mass of the sample, g.

In the denitrification evaluation experiment of the adsorbent, Jinxi Petrochemical deeply hydrogenated diesel oil was used as the raw material to add quinoline, aniline, pyridine, indole, etc. After compounding, it is made into a simulated catalytic diesel raw material containing 500ppm of basic nitrogen and 100ppm of neutral nitrogen.

Table 1 Comparison table of denitrification effect

Denitrification agent Inlet alkali nitrogen content (ppm) Export alkali nitrogen content (ppm) Nitrogen removal rate% Raw material consumption (ml) Airspeed (h ^-1 ) Adsorption capacity (wt%) Example 1 500 not detected >99.9 461 1.0 1.8 Example 2 500 not detected >99.9 564 1.0 2.2 Example 3 500 not detected >99.9 487 1.0 1.9 Example 4 500 not detected >99.9 385 1.0 1.5 Example 5 500 not detected >99.9 410 1.0 1.6 Example 6 500 not detected >99.9 380 1.0 1.5

The evaluation test mainly investigates the denitrification effects of the 6 groups of denitrification agents prepared in the above-mentioned examples 1 to 6. During the test, when alkali nitrogen is detected at the outlet and the denitrification rate drops to 80%, the test is stopped and the denitrification rate is considered to be 80%. Nitrogen has failed. It can be seen from Table 1 that the denitrification agent of the present invention has a high denitrification rate and a high nitrogen adsorption capacity, which can be as high as 2.2%.

Although the present invention has been described in detail through the above-mentioned specific embodiments, those skilled in the art should understand that any changes in form and details made on this basis that do not exceed the scope of protection of the claims belong to The scope to be protected by the present invention.

Claims (10)

1. a denitrifier is characterized in that, described denitrifier is by 60～90wt%SiO ₂With 10～40wt%Al ₂O ₃Form; The preparation method of described denitrifier, it comprises the steps:

(a) in aluminum-containing raw material, add suitable quantity of water, the mol ratio of aluminium oxide is 110～280 in described water and the product, is hydrolyzed under 83～87 ℃, adds salpeter solution afterwards and carries out dispergation, the 1h at least that under 90～95 ℃, is hydrolyzed again, the cooling back generates colloidal sol product I;

(b) in silicon-containing material, add an amount of absolute ethyl alcohol, the mass ratio of described absolute ethyl alcohol and silicon-containing material is 0.5～0.7, above-mentioned substance is stirred, add volume ratio then and be 1: 1 second alcohol and water, in the solution in the total water yield and the product mol ratio of silica be 6～10, adding salpeter solution afterwards, to regulate the pH value of above-mentioned solution be 3, stirs to obtain colloidal sol product II;

(c) product I and product II are mixed stirring, and add proper amount of surfactant, SiO in described surfactant and the product ₂Mol ratio be 0.15～0.35, stir 3～10h and directly generate jel product III, above-mentioned product III is worn out in 50～70 ℃;

(d) above-mentioned product III after aging is carried out drying under reduced pressure 0.5d at least in 30～50 ℃, get final product in 500～600 ℃ of roasting 3～5h after the moulding.

2. denitrifier according to claim 1 is characterized in that, SiO in the described denitrifier ₂Content be 80wt%, Al ₂O ₃Content be 20wt%.

3. denitrifier according to claim 1 and 2 is characterized in that, the specific area of described denitrifier is 500～1000m ²/ g, pore volume are 0.6～1.2ml/g.

4. denitrifier according to claim 3 is characterized in that, the percentage of the aperture 3-10nm of described denitrifier is greater than 80%.

5. denitrifier according to claim 1 is characterized in that, in the described step (a) with aluminum-containing raw material in 85 ℃ of following hydrolysis 1h, 1～2.5h is hydrolyzed under 90～95 ℃.

6. denitrifier according to claim 1 is characterized in that, the ageing time in the described step (c) is 2～3d.

7. denitrifier according to claim 1 is characterized in that, in the described step (d) the product III after the moulding is carried out roasting in 550 ℃.

8. denitrifier according to claim 1 is characterized in that, described aluminum-containing raw material is one or both in aluminum nitrate, the aluminium isopropoxide; Described silicon-containing material is one or both in methyl silicate, the ethyl orthosilicate.

9. denitrifier according to claim 1 is characterized in that, described surfactant is that molecular weight is not higher than 600 organic amine surfactant.

10. denitrifier according to claim 9, it is characterized in that it is to be selected from dodecyl benzyl dimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, softex kw, cetyl trimethyl ammonium chloride, myristyl dimethyl benzyl ammonium chloride, the two octyl alkyl dimethyl ammonium chloride one or more that described molecular weight is not higher than 600 organic amine surfactant.